BACTERICIDAL FLUORESCENCE EXCITED BY X-RAYS

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  • 1Henry Phipps Institute of the University of Pennsylvania, Philadelphia.

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Physical Methods for Controlling Microbial Growth: Radiation and Filtration

Radiation and filtration are essential tools for microbial control, targeting microorganisms through distinct mechanisms. Radiation eliminates microbes by damaging their DNA, either killing them or inhibiting their growth. Based on wavelength, radiation is classified into two types: nonionizing and ionizing radiation.Non-ionizing radiation, such as UV radiation (200–400 nm), is absorbed by DNA, causing defects that effectively disinfect surfaces, air, and water, including safety cabinets.
X-ray Imaging01:24

X-ray Imaging

German physicist Wilhelm Röntgen (1845–1923) was experimenting with electrical current when he discovered that a mysterious and invisible "ray" would pass through his flesh but leave an outline of his bones on a screen coated with a metal compound. In 1895, Röntgen made the first durable record of the internal parts of a living human: an "X-ray" image (as it came to be called) of his wife’s hand. Scientists worldwide quickly began their own experiments with X-rays, and by 1900, X-ray was widely...
Fluorescence and Phosphorescence: Instrumentation01:25

Fluorescence and Phosphorescence: Instrumentation

Fluorometers and spectrofluorometers are two types of instruments used for measuring molecular fluorescence. These instruments differ in how they select excitation and emission wavelengths and the type of light sources they utilize. Fluorometers use absorption interference filters to choose excitation and emission wavelengths. The excitation source in a fluorometer is typically a low-pressure mercury vapor lamp that emits intense lines distributed throughout the ultraviolet and visible regions.